Disk drives are typically sealed to protect the drive from dust, condensation and other sources of contamination. Various approaches to sealing disk drive assemblies are known. One such approach is the use of a tape seal that wraps around the outside periphery of the disk drive housing. However, sometimes the integrity of tape seals is not sufficiently reliable.
Another approach has been the use of a gasket that is formed in place on the underside periphery of the top cover. Once the gasket has been formed, the disk drive top cover is pushed down axially onto the top end of the baseplate wall, thereby compressing the formed-in-place gasket between the top cover and the top end of baseplate wall. One drawback to this approach is that a relatively thick baseplate wall (e.g., 2 mm for 1.8-inch drives and 1 mm for 1-inch drives) is required to accommodate the o-ring. This leaves less available space within the disk drive assembly for use by other components, which is particularly disadvantageous in the context of microdrives (e.g., 1-inch drives) where internal drive space is more limited. As such, what is needed is an improved top cover gasket which overcomes one or more of the aforementioned drawbacks.